Effect of spin transfer torque on the magnetic domain wall ferromagnetic resonance frequency in the nanowires

TL;DR

This study uses micromagnetic simulations to show how spin transfer torque affects the ferromagnetic resonance frequency of domain walls in nanowires, revealing significant frequency shifts even when the domain wall is pinned.

Contribution

It provides the first detailed analysis of how spin transfer torque influences domain wall resonance frequency in pinned conditions, excluding extrinsic defect effects.

Findings

Resonance frequency decreases with increasing current density.

Frequency variation exceeds 1.6 GHz due to spin transfer torque.

Pinned domain walls show significant resonance shifts independent of extrinsic defects.

Abstract

We investigate the influence of the domain wall ferromagnetic resonance frequency on the spin transfer torque in a ferromagnetic nanowire. By employing micromagnetic simulations with the spin transfer torque, we find that the domain wall resonance frequency decreases with increasing spin polarized current density, when there is no change in the resonance frequency of the domain itself. Surprisingly, the variation of the resonance frequency is remarkable (> 1.6 GHz) with the spin transfer torque even though the domain wall is pinned. Since the presented domain wall ferromagnetic resonance study has been performed for the pinned domain wall, the contributions of extrinsic defects are excluded. It is strong advantages of the present study, since the effects of extrinsic pinning sites are inevitable in the imaging or transport measurements.